The present invention relates to a process and a device for the production of labels as well as a label obtainable by this process.
Products packed in glass or plastic containers are frequently identified by labels adhered to the packaging. However, in the pharmaceutical field in particular, because of the generally small pack sizes the surface of the package is often insufficient to accommodate the wealth of information necessary for adequate product identification on a single-layer adhered label. Therefore, so-called booklet labels are widely used nowadays. These are labels with a multilayered structure comprising a booklet, i.e. a small book of several pages or a single- or multiple-folded sheet. Whereas the area of the booklet is limited by the surface available for labelling, e.g. the casing surface of a cylindrical or prismatic box or bottle, the surface on which information may be printed can be increased many times by a larger number of booklet pages. To protect the booklet, which is generally made of paper, against damage and soiling, it is generally covered with a transparent plastic foil.
Such a label as well as a process for its production is disclosed in EP 0 232 054 B1. The label comprises a support piece which is self-adhesive on its underside and a single- or multiple-folded sheet which is fastened to the upper side of the support piece by means of a transparent self-adhesive foil.
For production of the labels the folded small sheets are provided in the form of a stack and placed on the upper side of a support web which has a self-adhesive coating on its underside and is provided with tear-off material. The support web together with the small sheets is then coated with self-adhesive laminate on the underside. The laminate is also provided in the form of a web in this case and is pressed on by means of a pressure roller. The individual labels are punched out by means of a punching roller, the punch cuts separating the laminate and the support web while leaving the tear-off material intact, so that after the lattice formed between the labels is torn off, there is a web of tear-off material in place on which the labels are disposed. The process is performed continuously by unwinding the support web from a roll and directing it over a production line, along which said production steps occur.
However, such a production process is associated with certain problems. The small sheets must be produced separately and provided in the form of a stack which is expensive. There is also the risk here, amongst other things, of waste being generated as a result of incorrect or wrongly oriented small sheets being included in the stack. Moreover, the devices necessary for placement of the small sheets onto the support web are complicated, which results in increased expense of the process. Thus, it has been proposed, for example, to take up the small sheet from the stack using arms provided with a vacuum suction mechanism and place them on the support web. One particular difficulty is to position the folded small sheets exactly on the web and prevent the small sheets from slipping during or before lamination. Expensive measures to overcome this difficulty are tried, for instance using small sheets which have a pressure-sensitive adhesive on their underside and are pressed onto the web on placement, or applying small quantities of adhesive onto the upper side of the support web before applying the small sheets. The consequence of this is a further increase in expense of the process or of the devices necessary for this, while the possibility of labels being wrongly aligned on the web still cannot be fully excluded.
A further label of the above-described type as well as a process for its production is disclosed in EP 0 839 365 B1. The label has a folded small sheet or bound booklet, which is fastened on the upper side of a base made of tear-off material by means of a self-adhesive laminate. Further small sheets can be inserted into the folded small sheet. Moreover, a support piece which is self-adhesive on its underside can be provided, to which the small sheet is attached by means of the laminate.
For production of the labels, folded sheets are placed individually onto a web of tear-off material or support pieces which are self-adhesive on their underside already located thereon. A self-adhesive web of foil is laminated onto this and labels of the above-described type are punched out.
While it is possible to use sheets of a width which allows several small label sheets disposed in a row next to one another on the tear-off material to be cut out of a single sheet after lamination, the fundamental technical problem still remains that individual sheets have to be placed as exactly as possible on a web, which frequently does not occur with adequate precision at a feasible technical expense.
Moreover, there is the problem of checking the printed inscription which in the case of label booklets is generally distributed over all pages. Copies containing errors can often not be detected, since in the placement of already pre-folded small sheets the print of the pages lying on the inside is excluded from a simple check.